1. Field of the Invention
This invention is concerned with a chemical process. More particularly, the instant invention involves a process for removing inpurities from alkali metal and ammonium salts of cefamandole and the subsequent conversion of such salts to pure crystalline cefamandole.
2. Prior Art
Cefamandole is a member of the class of antibiotics known as cephalosporins. Many of the cephalosporins are highly useful antiinfectives and are widely used for the treatment of disease in man and animals. Cefamandole bodes well to become one of the more useful members of this group of semi-synthetic antibiotics inasmuch as it has superior activity against a wide range of pathological organisms.
Crystalline lithium and ammonium salts of cefamandole can be prepared readily from cefamandole synthesized from 7-amino-cephalosporanic acid (7ACA) or described in U.S. Pat. No. 3,641,021. While sodium and potassium salts of cefamandole can also be prepared from such starting material, they are not crystalline; they are amorphous. Neither lithium nor ammonium cations were thought to be medically preferred. On the other hand, either sodium or potassium salts are medically suitable for parenteral administration, and of these, sodium is preferred. It was discovered, however, that crystalline sodium cefamandole could be prepared from highly pure cefamandole; cefamandole from which the impurities, from the reaction converting the 7ACA to cefamandole, had been removed. A process for the preparation of crystalline sodium cefamandole from highly pure cefamandole is described in U.S. patent application Ser. No. 642,922, now U.S. Pat. No. 4,054,738.
Accordingly, it is an object of this invention to provide a process for preparing cefamandole of sufficient purity for conversion to crystalline sodium cefamandole.